Inspection of different kinds of cereals and other crops is today made all over the world to determine the quality of the cereals in commercial transactions and handling. The inspection aims at examining a selected representative sample from a large consignment and determining the presence of non-desirable grains and particles. The non-approved grains and particles are classified and the quantity of each class is determined. Owing to the distribution of the various grains, the sample and, thus, the consignment will be given a grading which is a decisive factor in connection with payment and handling of the consignment.
Today most cereal inspections are carried out entirely manually. A skilled inspector has often passed through a comprehensive education of many years. Nevertheless there are great deviations in the analyses/classifications between different inspectors owing to, among other things, personal assessments and varying conditions of lighting. Deviations also occur in each individual inspector because of, for example, the degree of fatigue.
It is particularly difficult to detect cracking in the grains. A special problem is to detect cracks in rice. An inspector cannot detect cracked grains with the naked eye. Cracked grains can be detected by grains being placed on a sheet of glass with an inclined mirror underneath. When the grain is illuminated from above, cracks can be detected when looking at the grain in the mirror. According to another method, cracks can be detected if the grain is placed on a shimmering blue layout table. The inspector can then detect cracks by looking at the grain from different angles. Both methods imply that the inspector must be assisted by special illumination and place the grains so that they are correctly illuminated. This means that the analyzing process is slowed down significantly since the analysis of each grain takes a long time.
It is desirable for the analysis of grains to be automated in order to reduce the deviations and create a more stable situation involving a more transparent grading process. This means that a reliable method of detecting cracks in grains in an automated manner is needed. There is today no satisfactory method of detecting cracks, which means that an inspector still has an important role.